When Logan and Jessica arrive at the ice cave, they are wet, so they take off their clothes and wrap themselves in animal skin to get warm. Jessica gets naked and Logan takes off his shirt but not his pants. But when they sit down we can see he is not wearing any pants.

Michael York (Logan 5), Richard Jordan (Francis 7) and Michael Anderson Jr.(Doc), were all over 30 years old when they made the film (the premise of which is that no-one is allowed to live past the age of 30).